ABSTRACT

Local heat transfer coefficients were measured in the separating, reattaching and redeveloping axisymmetric regions of turbulent boundary layer over the wall of convex cylinders with a uniform wall heat flux. Measurements were made with three different diameters of cylinders with five different diameters of the obstructions. The range of Reynolds number based on step height was between 4000 to 100000.
The study demonstrates that the maximum Nusselt number increases with decreasing cylinder radius and are always greater than those for the two-dimensional backward-facing step flow at the same conditions of the step height and flow velocity. It was also observed that the heat transfer in the redeveloping region increases with an increase in the radius convex curvature. An empirical equation is proposed for the Nusselt number at the reattachment point, correlated as a function of the Reynolds number and the diameter ratio.